Liquid Ejecting Apparatus Filter Placement for Pressure Loss Reduction
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Solution Overview
Problem
In liquid ejecting apparatuses, such as ink jet recording devices, the combination of filters in the head unit and back pressure control unit leads to increased pressure loss and bubble accumulation, limiting the versatility and increasing costs.
Innovation Solution
A design where a filter is placed only in the second liquid flow channel of the head unit, without one between the discharge channel of the back pressure control unit and the second opening of the back pressure control element, along with a second filter with a higher opening ratio between the liquid introduction opening and the first opening of the back pressure control unit, to minimize pressure loss and prevent foreign matter entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If filters are provided in both the back pressure control unit and the head unit, then foreign matter removal is improved, but pressure loss increases and bubbles accumulate
Solution Approach 1:
The patent extracts one filter from the back pressure control unit, leaving only a filter in the head unit. This removes the harmful effect of dual-filter pressure loss and bubble accumulation while preserving the essential function of foreign matter removal through the remaining filter in the head unit.
2Reliability
If filters are provided in both the back pressure control unit and the head unit, then foreign matter removal is improved, but device complexity increases
Solution Approach 1:
The patent extracts one filter from the back pressure control unit, reducing the total number of filters from two to one. This simplifies the device structure and reduces complexity while maintaining adequate foreign matter removal capability through the filter positioned in the head unit.
3Reliability
If a filter with low opening ratio is used to remove foreign matter, then foreign matter removal is improved, but pressure loss increases
Solution Approach 1:
The patent applies local quality by positioning the filter with appropriate filtration characteristics specifically in the head unit where it is most needed for protecting the nozzle and pressure generation chamber. The filter is placed at the location where foreign matter removal provides maximum benefit while minimizing overall system pressure loss.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces pressure loss, prevents bubble accumulation, and minimizes the risk of filter-related malfunctions, enhancing the apparatus's versatility and reducing costs by allowing for easier maintenance and the reduction of head unit types.
Implementation Method 1
a first filter disposed in the second liquid flow channel
Implementation Method 2
a second filter with a higher opening ratio between the liquid introduction opening and the first opening of the back pressure control unit
Implementation Method 3
a back pressure control element that has a first opening, a second opening, a first liquid flow channel that enables the first opening and the second opening to communicate with each other, and a valve body that controls the flow of liquid in the first liquid flow channel
Implementation Method 4
a pressure generation element that causes a pressure change in liquid in the pressure generation chamber and causes the liquid to be ejected from the nozzle
Data Source
AI summary
A liquid ejecting apparatus includes a back pressure control unit including a back pressure control element that has a first opening, a second opening, a first liquid flow channel that enables the first opening and the second opening to communicate with each other, and a valve body that controls the flow of liquid in the first liquid flow channel, and a housing that houses the back pressure control element and in which a liquid introduction opening that communicates with the first opening and a discharge channel that communicates with the second opening are formed, and a head unit including a third opening connected to the discharge channel of the back pressure control unit, a second liquid flow channel that communicates with the third opening, a first filter disposed in the second liquid flow channel, a pressure generation chamber, a nozzle, and a pressure generation element.